1. Technical Field
The present invention relates generally to a method and apparatus which maintains a dental drill or other dental tool, and more particularly to a unit that provides a maintenance treatment to the dental tool.
2. Background art
Hand held dental tools, such as high speed and low speed dental drill or handpieces, are in wide use, and a dentist will commonly use the same dental tool especially the drills for performing several dental operations on different patients in a short period of time. There is a need for a convenient and effective method to help the dentist and his or her staff to maintain and sanitize the tools between operations on patients. Furthermore, a routine is needed that would help to insure that all portions of a handpiece which may have been exposed to one patient's mouth are disinfected prior to use with other patients. Such additional procedure would provide one more safeguard against the spread of disease.
A search of the U.S. Patent literature has developed the following patents:
U.S. Pat. No. 3,646,678 (McAlister) shows a dental drill wherein compressed air from an external source is pumped through the drill, through an air turbine which powers the drill, into a vacuum tube 44 within the drill. In the vacuum tube 44, the air is drawn through a valve v to a vacuum pump. Coolant water, which has been first sprayed on a tooth-drill bit interface within the patient's mouth, is drawn into the drill, through a tube, into the line 44, and through the line 44 to the vacuum pump. In a back flushing mode, the flow in the line 44 is reversed. Medicated liquid flows from a source through the valve v backwardly through the line 44 through the drill and to the tooth-drill bit interface where the medicated liquid is dispensed.
U.S. Pat. No. 3,757,425 (Kraft) shows a system in which, when a selected dental tool among 10, 11, 12, 13, is lifted from a pedestal, its associated spool valve 16, 17, 18, 19, becomes operable. Air bearings in the particular tools 10, 11 are continuously supplied with air during the operation. By depressing a single foot pedal, the dentist causes predetermined liquids to flow to the selected tool. For example, if the dentist picks up the tool 10 and presses the pedal, the tool 10 receives plain water. The tools 11 and 12 also receive water. The tool 13 receives a liquid detergent. The tool 12 and 13, receive lubricating oil for their bearings. Upon the same movement of the pedal all four drills receive air necessary to drive the drill. The liquid lubricating oil runs through a line to a nozzle 170 (shown in FIG. 8) which is located in a middle of a drive air line leading to the air turbine in the drill. The venturi effect of the air passing by the nozzle 170 helps disperse the oil into a fine mist, with the air/oil mixture continuing on into the turbine, where the turbine is lubricated.
U.S. Pat. No. 3,556,669 (Valeska) shows a system the major thrust of which (as stated in col.2, ln. 70-col. 3 ln. 5) is to provide a control system that supplies air having the proper pressure and oil content for dental instruments of any manufacturer by suitable adjustment to the system. Oil is mixed with air in a lubricator 163 using a venturi principle and having an oil drop adjustment screw. Fine tuning of the air-oil mixture is provided by an adjustable valve 96 which in effect short circuits the lubricator 163 in a manner to lower the pressure differential therein, thereby providing a step down adjustment for oil content. Tools 12 and 14, which are the tools requiring oil, are able to be supplied with either oiled air or dry air. A shutoff valve 171 in the line to the drill 12 shuts off oiled air, so that the drill 12 may be driven on dry air. When a valve 178 is closed and a valve 180 is open, dry air alone is supplied to the drill 14. When the valve 178 is open, and the valve 180 is closed, oiled air is supplied to the drill 14.
U.S. Pat. No. 3,256,603 (White) shows a system that sends lubricated dry air through the drive turbine of a dental drill, and which directs water-misted coolant air which is discharged at the head of the drill (col. 7 lns. 21-26).
U.S. Pat. No. 3,106,021 (Borden) shows a control unit for a dental tool where a lubricant is applied to the stream of air which flows to drive the dental tool. The lubricant is directed upwardly through a gooseneck 116 where the lubricant drips into an area to be mixed in air in an air passageway. The flow of the oil can be controlled by the setting of a needle valve.
U.S. Pat. No. 4,544,355 and also U.S. Pat. No. 4,486,174 both issued to Eibofner show a container 1 that contains a liquid maintenance medium (which is a cleaning medium or lubricating medium) and a drive medium, such as compressed air or freon. The maintenance medium is forced through a nozzle where the maintenance medium enters the dental tool.